In short term, move could boost licensing and TV payments, but whether there are enough U.K. fans to support a team remains unknown.

The National Football League reclaimed Los Angeles last week. The St. Louis Rams will return to their former home for the 2016 season. The 21-year absence of a team in LA left a huge hole in the footprint of a wildly popular league with global aspirations. With that matter settled, speculation about NFL expansion beyond the U.S. will undoubtedly...